Fifteenmile Action to Stabilize Temperatures FAST 2024-2025

This project serves Fifteenmile Creek in Wasco County, home to ESA listed steelhead. Fifteenmile Creek is subject to high temperatures and low flows in summer, which is exacerbated by irrigation withdrawals. FAST or (Fifteenmile Action to Stabilize Temperatures) is a unique plan that temporarily increases streamflow by having irrigators voluntarily shut off irrigation during temperature spikes.
At the heart of the project is an ODFW-developed model that forecasts stream temperatures for the following week at four sites on Fifteenmile Creek and one site on Eightmile Creek. When temperatures lethal to juvenile steelhead are predicted at two or more sites, for two or more days within the next three days, the FAST Coordinator issues an alert to participating irrigators. The alert prompts participants to stop irrigation to increase instream flows and lessen the intensity of predicted stream temperatures.
This project offers compensation to participants to alleviate any potential crop damage during these alerts as well as any inconvenience. The primary benefit to irrigators modifying water use during times of critical low flow is reducing personal liability under the ESA. The FAST Coordinator performs administration and monitoring duties for FAST. This includes engaging irrigators in outreach, presenting changes and results at all associated meetings, and providing contracting services. Additionally, starting this year the SWCD will offer assistance to landowners in filling out instream leasing agreements and renewals. This service would be free of charge, but would not offer compensation for the leased water as a traditional instream leasing program would.
FAST excels in interagency collaboration. The Freshwater Trust was instrumental in the development of the FAST program by providing technical assistance. FAST is developed through the Fifteenmile Watershed Council and administered through the Wasco County SWCD. Other partners include ODFW, and OWRD.

The FAST program is a voluntary, seasonally contracted flow restoration program. Irrigators sign up for the program before the irrigation season begins each year, and are given monetary compensation in exchange for their agreement to shut off irrigation use during periods of warm instream temperatures as defined by a statistical stream temperature model developed by ODFW. This cessation of irrigation causes immediate impacts to instream flows during periods critical to the survival of native salmonids, buffering the impacts of periods of low flows combined with high temperature that are common within the region. A stream temperature alert is issued when stream temperatures reach 71.6°F in the upper portions of the creek, or 73.4°F in the lower portions of the creek. In the event an alert is triggered, irrigators must remain shut off for at least 3 days from the date the alert was issued; but can be required to be shut off for longer if the period of concerning stream temperatures extend for longer than 3 days.

The observed benefit of a given alert depends greatly on several different factors at play within the watershed, but near immediate impacts to instream flow as great as 3cfs have been observed in previous alerts. When considering baseflows during the summer months in Fifteenmile Creek frequently reach as low as 2 cfs in certain areas, the issuing of an alert that returns 3cfs of instream flows that would normally be diverted to irrigation can greatly increase the total amount of flow present within the creek. This increased water availability can provide several benefits to native salmonid populations, including improved summer passage, improved instream flows, and subsequently; improved instream temperature and dissolved oxygen levels as the thermal capacity of the stream increases with water availability.